A typical LCD device has the advantages of portability, low power consumption, and low radiation, and has been widely used in various portable information products such as notebooks, personal digital assistants (PDAs), video cameras and the like. A conventional LCD device such as a twisted nematic (TN) LCD device commonly has a rather limited viewing angle. Thus, the MVA-type LCD device was developed to improve the viewing angle.
Referring to FIG. 11 and FIG. 12, aspects of a typical MVA-type LCD device 500 are shown. The LCD device 500 includes a first substrate assembly 510, a second substrate assembly 520 generally facing the first substrate assembly 510, and a liquid crystal layer 530 sandwiched between the two substrate assemblies 510, 520. The liquid crystal layer 530 includes a plurality of liquid crystal molecules 531.
The first substrate assembly 510 includes a first transparent substrate 511, a color filter 513, a common electrode 515, and a plurality of first protrusions 519, arranged in that order from top to bottom. The color filter 513 includes a plurality of red filter units (not shown), a plurality of green filter units (not shown), and a plurality of blue filter units (not shown). The first protrusions 519 each have a triangular section configuration, and are arranged along a plurality of V-shaped paths.
The second substrate assembly 520 includes a second transparent substrate 521, a plurality of gate lines 522 that are parallel to each other and that each extend parallel to a first direction, a plurality of first data lines 523 that are parallel to each other and that each extend parallel to a second direction that is orthogonal to the first direction, a plurality of second data lines 524 that are parallel to each other and that each extend parallel to the second direction, a plurality of first thin film transistors (TFTs) 525, a plurality of second TFTs 526, a plurality of first pixel electrodes 527, a plurality of second pixel electrodes 528, and a plurality of second protrusions 529.
The first data lines 523 and the second data lines 524 are arranged alternately. Every two adjacent first data lines 523 together with every two adjacent gate lines 522 form a rectangular area, which is defined as a pixel unit 50. Each pixel unit 50 corresponds to a filter unit of the color filter 513. Each second data line 524 is disposed across a middle of a corresponding pixel unit 50, and divides the pixel unit 50 into a first sub-pixel unit 501 and a second sub-pixel unit 502.
The first TFTs 525 are located in the vicinity of intersections of the first data lines 523 and the gate lines 522, respectively. The second TFTs 526 are located in the vicinity of intersections of the second data lines 524 and the gate lines 522, respectively. The first pixel electrodes 527 are located in the first sub-pixel units 501, and are connected to the first TFTs 525, respectively. The second pixel electrodes 528 are disposed in the second sub-pixel units 502, and are connected to the second TFTs 526, respectively. The first data lines 523 are used to apply first data voltages to the first pixel electrodes 527 through the respective first TFTs 525. The second data lines 524 are used to apply second data voltages to the second pixel electrodes 528 through the respective second TFTs 526. The second protrusions 529 of the second substrate assembly 520 are arranged alternately with the first protrusions 519 of the first substrate assembly 510.
Referring also to FIG. 13, this is a top-down view of orientations of four of the liquid crystal molecules 531, according to the protrusions 519, 529. When corresponding voltages are applied to the pixel electrodes 527, 528 and the common electrode 513, an electric field is generated therebetween. The liquid crystal molecules 531 twist according to the electric field. The liquid crystal molecules 531 are guided by the protrusions 519, 529 and thereby become aligned in four different directions. Thus four domains are defined according to the protrusions 519, 529.
Further, because the voltages of the first pixel electrodes 527 are different from the voltages of the second pixel electrodes 528 in each frame, tilt angles θ1 of the liquid crystal molecules 531 in the first sub-pixel units 501 are different from tilt angles θ2 of the liquid crystal molecules 531 in the second sub-pixel units 502. Thus, a total of eight domains are defined in each pixel unit 50. That is, the LCD device 500 achieves 8-domain vertical alignment.
However, each pixel unit 50 needs two data lines 523, 524 and two TFTs 525, 526 for the MVA-type LCD device 500 to be able to achieve 8-domain vertical alignment. The layout of the data lines 523, 524 is complicated, and the cost of the LCD device 500 is correspondingly high. Furthermore, an aperture ratio of the LCD 500 is reduced.
It is desired to provide an improved MVA-type LCD device which can overcome the above-described deficiencies.